9 Operating System
Prerequisites: none. This chapter stands on its own.
See also: Chapter 10, Chapter 11, Chapter 14.
Purpose
It’s ten at night and a project is due tomorrow. You open your laptop, and it announces that it needs to restart to finish installing updates. Forty minutes later it’s back, Jupyter won’t launch, and a pop-up says your disk is almost full. You search the error, find a tutorial, and its first step tells you to open a settings panel your computer doesn’t seem to have.
None of that means you’re bad with computers. The operating system is the layer everything else sits on, and nobody sits students down and explains how to look after it. The good news is that most of what goes wrong with it is predictable: an update at the wrong moment, a full disk, a backup that was never set up, a setting nobody showed you. A few habits, set up once and checked for a few minutes a week, prevent most of it.
This chapter is those habits, for Windows and macOS: finding settings, knowing your version, keeping disk space free, updates, basic security, backups, a troubleshooting routine, and a semester schedule. It doesn’t cover the file system (Chapter 10), the command line (Chapter 11), or installing Python packages (Chapter 14), though it points to each where they meet. On Linux, the ideas carry over even where the menus don’t.
Why read this chapter
- A tutorial told you to open “System Preferences” or showed a Windows screen that looks nothing like yours, and you’re stuck on step one.
- Your laptop says the disk is almost full in the week a project is due, and you can’t see what’s using the space (hint: it may be five old Python environments and a download cache).
- An update restarted your computer during an exam or took forty minutes the night before a deadline, and you’d like updates to happen on your schedule instead.
- You’ve never set up a backup, and the thought of your laptop being stolen with your thesis on it makes your stomach drop.
- Your Mac won’t open an app you downloaded because Apple “cannot check it for malicious software,” and you’re not sure whether to trust it or how to get past the warning.
- A TA asked what version of Windows or macOS you’re running, and you didn’t know where to look.
- Someone told you to install a “cleaner” or a driver-updater to speed things up, and you’d like to know why that’s a bad idea before you try it.
- Something is broken right now, and you want a short list of what to try first before you panic.
Running theme: stability comes from routines
Most operating system problems are predictable, so most of them are preventable. You don’t need to be perfect; you need a few small habits you actually keep.
9.1 What the operating system does for you
When you type, click, open a program, or save a file, you’re asking the operating system to do it. It’s the software between your apps and your hardware. It handles the keyboard and the screen, launches and stops programs, and talks to your Wi-Fi, audio, and storage through small programs called device drivers. It keeps user accounts separate and enforces the permissions that decide who can read or change what. It runs your network connections and your file system, ships its own updates and malware protection, and provides the recovery tools that get you back to a working state when something goes badly wrong.
It helps to split that list in two. You’re in charge of your settings, updates, backups, storage, and accounts: the levers that decide whether your computer stays stable, and the subject of the rest of this chapter. What you should leave alone matters just as much, because the internet is full of confident advice that makes things worse. Third-party “cleaner” and “optimizer” apps, registry tweaks copied from forum posts, drivers from sites that aren’t the hardware maker’s, and security settings you can’t explain in one sentence have each hurt far more people than they’ve helped. Many cleaners are what security researchers call potentially unwanted programs: they nag, upsell, and sometimes delete things your system needed. The rule of thumb is simple. If you don’t understand what a change does, don’t make it.
9.2 Getting oriented: where settings live
Here’s a frustration nearly everyone hits: the instructions name a menu you can’t find. Sometimes the tutorial was written for the other operating system; often it was written for an older version of yours, because both systems rearrange their settings every few years. Knowing where the settings hubs are, and how to search them, gets you past this almost every time.
On Windows, nearly everything you’ll change lives in the Settings app (the gear icon), with sections for System, Windows Update, Apps, Accounts, and Privacy & security. A separate Windows Security app holds the antivirus and firewall. The older Control Panel is still there too; Microsoft has been moving things out of it for years, but a few tools, including File History, still live in it.
On macOS, the hub is System Settings. Until macOS Ventura in 2022 it was called System Preferences and looked quite different, which is why so many tutorials and forum answers don’t match your screen. The sections you’ll use most are General, Privacy & Security, and Network. Beyond System Settings, a few utilities in Applications → Utilities come up often: Disk Utility for storage, System Information for everything about your hardware, and Activity Monitor for seeing what’s using your processor, memory, and battery right now.
The most useful skill on either system is one you may already have: both settings apps have a search box at the top. You don’t need to memorize the menus; you need a handful of keywords. Type update, backup, encryption, privacy, firewall, storage, or recovery, and you’ll usually land on the right page faster than you could click there.
9.3 Know your system: version, storage, and constraints
Before you troubleshoot anything, know three facts about your machine: its operating system version, its free storage, and where your files actually live. Help channels ask for them first, and plenty of mysterious failures trace back to one of them.
Check OS version and build
“What version are you on?” is the first question a TA or help forum will ask, and it matters for your own searching too. Adding “macOS 26.4” or “Windows 11 25H2” to an error message is often the difference between finding someone who solved your exact problem and finding nothing. The build number also lets you tell whether an update really installed.
Windows: Settings → System → About
— look under "Windows specifications" for "Version" and "OS build"
— or press Win+R, type "winver", press Enter
macOS: Apple menu → About This Mac
— shows the macOS name and version (for example, Tahoe 26.4)
— click the version number to see the build number
Write the version down somewhere, along with your device model: it’s part of the baseline note you’ll want the day something breaks.
Check storage health early and often
A surprising number of “my computer is broken” help requests turn out to be “my disk is completely full.” A full disk makes Python scripts fail with cryptic errors, browsers crash, updates stall, and notebooks quietly fail to save. So before you panic about anything else, check free space.
Windows: Settings → System → Storage
— shows total, used, and a breakdown by category
— "Temporary files" and "Downloads" are usually the easiest wins
macOS: System Settings → General → Storage
— the same breakdown, with recommendations, and an (i) button
next to each category for a closer lookA good rule of thumb is to keep at least 15 to 20 percent of your disk free. Many solid-state drives get slower as they fill up, and the operating system needs room of its own for virtual memory, caches, and the next update. At 1 or 2 percent free, even opening a large spreadsheet can fail. When you dip below the buffer, clear space before it becomes an emergency: empty Downloads, remove old installers, delete virtual environments you no longer need (Chapter 15), and uninstall apps you don’t use.
How much space your programming tools take
Nobody mentions this on the first day: the tools for data work are big, and they multiply. Every course asks for Python and a few packages, every project gets its own environment, and every installation leaves a cache behind. None of it shows up in your Documents folder, so the first sign is often a full disk in the week an assignment is due.
Some real numbers, measured on a Linux computer in September 2026 with Python 3.11 (sizes on Windows and macOS are in the same range):
| What | Space on disk |
|---|---|
| A virtual environment with pandas and the packages it needs | 177 MB |
| The same environment with matplotlib added | 273 MB |
| A virtual environment with JupyterLab and pandas (97 packages) | 390 MB |
| A fresh Miniforge (conda) installation, before you create any environments | 659 MB |
| Anaconda Distribution | at least 5 GB, by Anaconda’s own system requirements |
| pip’s download cache, after one day of installing the above | 172 MB |
One environment isn’t the problem; the pile is. Five course projects with a JupyterLab environment each come to about 2 GB before you add a single dataset. Add an editor and its extensions, a container tool (Chapter 15), and a second Python installation you forgot about, and a 256 GB laptop fills up fast.
See where the space went. The storage views above show categories. The terminal (Chapter 11) shows folders:
# macOS and Linux
du -sh ~/Projects/*/.venv # each project's environment
du -sh ~/miniforge3 ~/anaconda3 # conda installs, if any
df -h # free space on each disk
# Every system
pip cache info # pip's cache: where, how big
conda clean --all --dry-run # preview a conda cleanupDon’t worry if du says “No such file or directory” for one of those folders: it just means you don’t have that installation. On Windows, File Explorer shows a folder’s size under right-click → Properties, and PowerShell can total one for you:
$files = Get-ChildItem .venv -Recurse -File
($files | Measure-Object -Property Length -Sum).Sum / 1MB # size in MBReclaim it safely. Three kinds of space come back without breaking anything:
- Caches.
pip cache purgeempties pip’s download cache, andconda clean --allremoves the package files conda downloaded; on the fresh Miniforge installation above it freed 101 MB. Caches only save download time, and they refill as you install things. - Environments for finished projects. An environment can be rebuilt from a list of what it needs, so when a course ends, save that list (
pip freeze > requirements.txt) and delete the environment’s folder (Chapter 15). Keep the code and the data; the environment is disposable. - Duplicate Python installations. Python from python.org, Anaconda, Homebrew, and the Microsoft Store can all end up on one computer, each taking space and competing to be the
pythonyour terminal runs (Chapter 14). Keep one, and remove the others with their own uninstallers.
Anything else goes through “Storage cleanup (do no harm)” below: if you don’t know what a folder is for, don’t delete it.
What you actually need. For the workflows in this book, that’s one terminal (already on your computer), one Python installation with one way of making environments (Chapter 14), one editor (Chapter 12), Git (Chapter 31), and JupyterLab installed inside each project’s environment rather than globally (Chapter 16). Install anything else when a course or project asks for it, into that project’s environment, and remove it when the project is done.
This box is one school’s answers; if you’re somewhere else, use it as a template. Your IT office’s website almost certainly has its own software catalog (search your school’s name with “student software”), and it’s worth ten minutes to look up the same things: which programs are free to you, on how many devices, and whether they keep working after you graduate.
Before you pay for software, check OIT’s software catalog. Microsoft 365, including the desktop apps, is free to students and can be installed on up to five computers, five tablets, and five phones (OIT: Microsoft 365). The catalog also lists MATLAB, Tableau (for academic use), Overleaf, Qualtrics, ArcGIS, and the campus VPN at no cost to students. Where your files go, and what happens to them after you graduate, is in Section 10.7.
Understand local vs synced storage
Cloud sync tools, such as OneDrive on Windows, iCloud Drive on macOS, Google Drive, and Dropbox, can leave a file’s name on your disk while its contents stay in the cloud, which breaks code that tries to read it. How to tell the difference, and how to keep project files fully on your computer, is in Section 10.7. From the operating system’s side the rule is short: sync is a convenience for documents, not a backup (see “Backups and recovery” below) and not a place to run projects from.
9.4 Updates and patching: best practices
Why updates matter
It’s tempting to click “Remind me tomorrow” forever. Updates arrive at bad moments, want a restart, and occasionally break something, so skipping them can feel like the safe choice. It isn’t. New security holes are found all the time, and installing the patches that fix them is the only practical defense; updates also fix the bugs that crash apps in mysterious ways. Skipping them just swaps a planned ten-minute restart for an unplanned evening of debugging at the worst possible moment.
Types of updates
Not every update deserves the same caution. A security update, or patch, is a small, targeted fix for a known hole: Microsoft ships them on the second Tuesday of each month, a routine known as Patch Tuesday, and Apple ships them as needed. They’re the top priority, so install them as soon as you can, even if they want a restart. Quality and point updates are small stability fixes and changes (Windows bundles them with the security fixes as its monthly “quality updates”; on a Mac they’re steps like macOS 26 to 26.4); install them whenever they show up. Feature updates and major upgrades are the big yearly releases: a new macOS each fall (26 to 27, in Apple’s example on its update page) and a Windows 11 feature update about once a year (the “25H2” in a version name means the second half of 2025). They sometimes break a workflow, so treat them as planned events on a calm day, never the morning of a deadline. Driver and firmware updates affect specific hardware (graphics, Wi-Fi, the laptop’s own firmware). Install them only through your operating system’s updater or from the hardware maker’s own website, never from third-party “driver finder” sites, which are a well-known source of malware. In short: major upgrades deserve planning; security patches deserve speed.
A safe patching workflow
If updates have ever ambushed you, the fix is to make them a small ritual you choose rather than an interruption you suffer.
First, back up, or confirm that your automatic backup ran in the last day or two, so you have a known-good state to return to.
Second, pick your moment: not ten minutes before an exam, not with unsaved work in twelve windows, but a time you can spare twenty minutes and a restart.
Third, install and let it finish, including every restart it asks for. Apple specifically warns against letting your Mac sleep or closing the lid mid-install.
Fourth, check that your tools still work. Open your browser and a spreadsheet, activate your conda or venv environment, launch Jupyter, and run one notebook. It’s the cheapest possible check, and it catches the common case where an update broke a Python interpreter or a Jupyter kernel.
Fifth, write down what changed if something now misbehaves. Both systems keep a list of installed updates (see “Recovering from a broken update” in the worked examples), and the date and version of the update that broke something is exactly what you’ll need when you ask for help.
Windows update practices
Windows Update lives in Settings → Windows Update, and a few controls there are worth knowing before an update surprises you. Active hours (under Advanced options) tell Windows when you usually use the computer, so it won’t restart for updates then; set them to cover your classes and study time. When an update is waiting, you can also schedule the restart. Pause updates holds everything for up to 35 days, according to Microsoft’s pause updates guide. That’s handy for finals week, but let the pause expire, because it holds back security fixes too. Optional updates (under Advanced options) often include drivers; skip them unless a piece of hardware is misbehaving.
macOS update practices
On a Mac, updates live in System Settings → General → Software Update. The (i) button next to Automatic Updates lets you choose whether to download new updates automatically, install macOS updates automatically, and install security responses and system files automatically. Turning all three on is a sensible default, so security fixes arrive without you having to remember. A major upgrade (26 to 27) still deserves a calm day, a fresh backup, and a check that the tools your courses need support it, and it’s worth opening Software Update now and then to see whether anything is waiting on you.
9.5 Security baseline for students
Accounts and authentication
If you do one thing for your security this semester, use a password manager. The standard advice, a long, unique password for every account, is impossible to follow from memory; a password manager makes it easy by inventing each password, remembering it, and filling it in. Good options include Apple’s Passwords app, the manager built into your browser, and dedicated tools such as Bitwarden or 1Password.
On top of that, turn on multi-factor authentication (MFA) for your important accounts: your university login, your email, GitHub, and any cloud service. One of the most common attacks on accounts is credential stuffing: a password leaked from some other site gets tried against yours. MFA stops that attack even when the password is right.
Finally, if your computer lets you, do your everyday work in a standard (non-administrator) account, and switch up to administrator only for specific jobs such as installing software or changing system settings. It’s the principle of least privilege: anything that goes wrong while you’re a standard user, including malware you didn’t notice, can do less damage.
Screen lock and physical security
Set your laptop to require a password when it wakes, and keep the auto-lock short: five minutes is reasonable for a personal laptop, less in a shared space. An unlocked laptop left in a café for two minutes is all it takes for someone to read your email or send messages as you. On Windows, look in Settings → Accounts → Sign-in options; on macOS, System Settings → Lock Screen.
Built-in protections
You almost certainly don’t need to buy antivirus software, because both systems ship with capable protection. On Windows, open the Windows Security app and check that “Virus & threat protection” (Microsoft Defender Antivirus) and the firewall are both on. On macOS, the protection works quietly in the background, with nothing to open: Apple’s malware defenses include XProtect, which detects and removes known malware, and Gatekeeper, which checks apps before they run. What you will see are permission prompts the first time an app wants your files, camera, microphone, or location. Read them before you click: refusing access an app doesn’t need is the easiest privacy win there is, and you can change your mind later under Privacy & Security.
Gatekeeper is also behind one of the more alarming messages a Mac can show: an app you downloaded “can’t be opened” because Apple “cannot check it for malicious software.” It sounds like an accusation, but usually it means the app wasn’t notarized (sent to Apple for an automated malware check), a step some small academic and open-source tools skip. Apple’s advice in Safely open apps on your Mac is to check for an App Store version or an updated release first. If you’re sure the app came from its real developer and hasn’t been tampered with, try to open it once, then go to System Settings → Privacy & Security, scroll down, and click Open Anyway. If the warning appears for something you didn’t mean to install, stop.
Encryption awareness (and recovery keys)
If your laptop is lost or stolen, disk encryption keeps your files private: without your password, the disk is unreadable, even in another machine. On Windows the feature is BitLocker, or device encryption on Windows Home; Microsoft turns device encryption on automatically on supported PCs when you sign in with a Microsoft or school account, but not with a local account. On macOS it’s FileVault, in System Settings → Privacy & Security. Check that yours is on.
Encryption brings one new thing you have to take seriously: the recovery key. It unlocks the disk if you forget your password or something goes wrong with your account. Microsoft usually saves it to your Microsoft account (Microsoft’s guide to finding your BitLocker recovery key shows where to look); FileVault lets you choose between your iCloud account and a key you keep yourself. Microsoft Support can’t recover a lost key, and Apple warns that without your password or the key, your files are lost for good. So find out where yours is, keep a copy somewhere other than the encrypted laptop, and never go ahead with an encryption change until you know how you’d recover from it. You’ll also need the key for some repair steps, such as starting Windows in safe mode on an encrypted PC.
Software installation hygiene
Install software only from places you can trust: the developer’s official website, the Microsoft Store or Mac App Store, or a reputable package manager (Homebrew on macOS, winget on Windows, conda or pip for Python). Free-download aggregator sites are a common source of malware, and they routinely bundle adware and toolbars with whatever you actually wanted. Keep your browser up to date, since it handles more untrusted input than any other program you run. And now and then, uninstall software you no longer use: every installed app is one more thing that could have a hole in it.
9.6 Backups and recovery: the student safety net
Losing a week of coursework to a dead drive, a stolen laptop, or a mistyped rm command is one of the most demoralizing things that can happen to a student. Setting up a backup takes minutes. If you only act on one section of this chapter, make it this one.
What backups are (and are not)
A backup is a separate copy of your data that you can restore. “Separate” is the important word: if the copy lives on the same drive as the original, whatever kills the original kills the copy. A backup worth trusting lives on a different device (an external drive, a network disk, a cloud backup service). Professionals follow the 3-2-1 rule: three copies of your data, on two different kinds of storage, with one somewhere else. For a student, your laptop plus an external backup drive plus a cloud copy of your important files gets you there.
Here’s the confusion that catches almost everyone: cloud sync is not the same thing as a backup. OneDrive, iCloud Drive, Google Drive, and Dropbox keep your files the same across devices, which is wonderful, but sync copies your mistakes too. Delete a file on your laptop and the cloud copy disappears moments later, and then the copy on your other devices does too. If ransomware scrambles your files, the sync client will dutifully copy the scrambled versions everywhere. Most sync services keep deleted files for a while: OneDrive keeps them for 30 days on personal accounts and 93 days on work or school accounts, and iCloud Drive’s Recently Deleted keeps them for 30 days. That’s a helpful safety margin, but it’s short, and it’s not a plan.
A backup worth having is automatic (you don’t have to remember to run it), regular (often enough that the worst case is losing an hour or a day of work, not a month), and restorable (you’ve actually checked that you can get a file back out).
Start free: the storage your school already gives you
You don’t have to buy anything to get a first layer of protection. Many universities give students cloud storage with their account, such as OneDrive or Google Drive, and often far more of it than a free personal account (Section 10.7 ends with one school’s numbers; your IT office’s pages have yours). Set up well, it covers the disaster people fear most: the laptop that dies, drowns, or gets stolen.
Two things make it more than plain sync. The first is putting your documents there automatically: OneDrive’s folder backup copies Desktop, Documents, Pictures, and a few other folders on Windows, and Desktop and Documents on a Mac; iCloud’s Desktop & Documents Folders does the same on a Mac, though a free iCloud account holds only 5 GB. The second is history. OneDrive keeps earlier versions of each file (for 30 days, Microsoft says), and a school account can usually restore the whole OneDrive to any point in the last 30 days, which is what you want after ransomware or a mass deletion. Google Drive keeps versions too. For code, the free layer is Git: push your projects to GitHub, and every commit lives somewhere other than your laptop (Chapter 31).
Now what it doesn’t do, because this is where “sync isn’t backup” bites. A deletion reaches the cloud within seconds, and you get the file back only while it’s still in the recycle bin or the version history, so a mistake you notice in week six may be gone for good. Your school runs the account: an administrator can turn versioning off, quotas change, and the account closes soon after you graduate (Section 10.7). And projects with virtual environments or Git repositories don’t belong in a synced folder at all; the same section explains why. So make it your first layer, not your only one. If you have an external drive, or can borrow one (any spare drive with enough room will do), add the tools below, which keep full, versioned copies on a drive nobody else controls.
Windows backups
Windows has two backup tools, and they do different jobs. Windows Backup (Settings → Accounts → Windows Backup) saves your folders, apps, and settings to OneDrive, so a new Windows PC can pick up where the old one left off. That’s great when you replace a laptop, but it isn’t a full backup, and it’s limited by your OneDrive storage.
For a real, versioned backup, add File History writing to an external drive. Plug in a USB drive, open Control Panel → System and Security → File History (or search for “File History” from the Start menu), choose the drive, and turn it on. File History then keeps copying your libraries and folders such as Documents, Pictures, and Desktop to the drive, and it keeps older versions, so you can go back to yesterday’s copy of a file, not just the latest one. To get a file back, right-click the folder it lived in and choose Restore previous versions.
Windows: Control Panel → System and Security → File History → Turn on
Settings → Accounts → Windows Backup (folders, apps, settings to OneDrive)macOS backups with Time Machine
Time Machine is about as easy as a good backup gets. Plug in an external drive (Apple suggests one with at least twice your Mac’s storage), open System Settings → General → Time Machine, click Add Backup Disk, and choose the drive. If Time Machine offers to erase it, say yes only if it’s a drive you’re dedicating to backups. Your Mac starts backing up right away and then keeps hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for all the months before that.
The underrated part is how easy Time Machine makes getting things back, disaster or not. Open the folder that held the file, then open the Time Machine app (search for it with Spotlight), step back through time, select what you want, and click Restore. That’s just as useful for “I overwrote a paragraph of my thesis two days ago” as it is for “my laptop died.”
macOS: System Settings → General → Time Machine → Add Backup Disk
Open the folder, then open the Time Machine app → RestoreTest your restore (the step most people skip)
A backup you’ve never restored from is a backup you hope works. So the first time you set one up, run a drill: delete a small, unimportant file and get it back (the worked example “Configuring backups and testing a restore” walks through it on both systems). It takes five minutes, and afterwards you know the system works and that you can drive it under stress.
Recovery tools when something really breaks
Both systems have a special recovery environment that starts even when the normal system won’t. You’ll rarely need it, which is exactly why it’s worth knowing how to get there before you do:
Windows: Settings → System → Recovery → Advanced startup → Restart now
(or hold Shift while you click Restart), then Troubleshoot:
— Advanced options → Startup Repair, for a PC that won't start
— Advanced options → Uninstall Updates, if trouble began with an update
— Advanced options → System Restore, if restore points were turned on
— Reset this PC, the last resort (keep or remove your files)
macOS: Apple silicon: shut down, then hold the power button until
"Loading startup options" appears → Options → Continue
Intel: turn on and immediately hold Command-R
— Disk Utility → First Aid, to repair the disk
— Restore from Time Machine
— Reinstall macOS (keeps your files in most cases)Microsoft’s recovery options page lists these from least to most disruptive, and Apple’s How to start up from macOS Recovery covers every Mac. Most people first think about recovery in the middle of an emergency, which is the worst time to learn. Write down how to reach it on your machine, and keep the note somewhere other than the machine, so you’re not searching “how do I boot my Mac into recovery” on your phone at midnight.
9.7 Performance and stability maintenance
You’ve probably seen ads promising to make your computer “faster.” The goal here is humbler: avoid the everyday conditions that make a computer slow or unreliable, using only changes that are safe and easy to undo.
Storage cleanup (do no harm)
Clean up what you can recognize: old installers in Downloads, duplicate copies of big files, finished projects, and the temporary files the system is happy to throw away. Start with the built-in storage tools, because they already know what’s safe to remove:
Windows: Settings → System → Storage
— "Cleanup recommendations" flags large files, unused apps,
and temporary files that are safe to remove
— Storage Sense can empty the Recycle Bin and old Downloads
automatically after a number of days you choose
macOS: System Settings → General → Storage
— "Recommendations" suggests ways to save space
— the (i) next to a category (Documents, Applications, and so on)
lists its files by size, so you can see what's eating spaceFor large files the built-in tools miss, a disk-usage visualizer such as WinDirStat on Windows, or GrandPerspective or DaisyDisk on macOS, draws your disk as a map where the biggest rectangles are the biggest files. It’s often the fastest way to find the 40 GB video project you forgot about.
Never delete files whose purpose you don’t know. System folders (C:\Windows on Windows; /System, /Library, and your own ~/Library on macOS) hold things your operating system and apps depend on. Deleting something in there to free space almost always breaks something later, and the breakage shows up far enough from the delete that you won’t connect the two.
Startup and background apps
If your laptop feels sluggish from the moment you log in, look at what starts with it. Every app that launches at login spends processor time, memory, and battery before you’ve opened a single window. Most added themselves when you installed them, without asking, and most don’t need to be there.
Windows: Settings → Apps → Startup
— turn off anything marked "High impact" that you don't need
right at login
— or: Task Manager → Startup apps tab, for the same list
macOS: System Settings → General → Login Items & Extensions
— "Open at Login" lists apps that open when you log in; select one
and click the minus button to remove it
— the section below it ("Allow in the Background" or "Background
Activity," depending on your macOS version) lists helpers that
run even when their app isn't openTurn off anything you don’t use regularly: updaters for apps you rarely open, sync clients for services you’ve stopped using, “companion apps” for a mouse or printer you no longer own. Log out and back in to see the difference. It’s all reversible: if something stops working properly, switch it back on in the same place.
Battery, heat, and laptop health
Laptops slow themselves down when they get hot, so a machine that’s always running its fans flat out is also always running slower than it should. The fix is rarely software; it’s airflow. Don’t work for long with the laptop on a blanket or a bed, where the cushion blocks the vents. Once or twice a year, with the laptop off, blow the dust out of the visible vents with a can of compressed air. If the fan is noticeably louder than it was a year ago, dust is the likely reason.
Your operating system can tell you how healthy the battery is. On a Mac laptop, System Settings → Battery shows its health, and System Information (hold Option and click the Apple menu) lists its cycle count under Power. Apple designs its batteries to keep up to 80 percent of their original capacity at their maximum cycle count, and recommends a replacement once you reach it. On Windows, the powercfg /batteryreport command writes an HTML report of your battery’s capacity over time:
# Windows (Command Prompt or PowerShell):
powercfg /batteryreport /output "battery.html"
# Open the generated file to see full charge capacity vs. design capacity.A failing charger can cause odd problems too: the machine suddenly sleeps, or the battery never quite reaches full. If you suspect the charger, try a different one you know works before blaming the laptop.
Drivers and peripherals
Drivers are how the operating system talks to your hardware, and they’re the one kind of update where installing from the wrong place can do real damage. The rule is short: install drivers only through your operating system’s updater or from the hardware maker’s official website, never from a “driver updater” site or app.
For printers, let the system detect the printer and use its built-in driver, and install the manufacturer’s app only if you need a feature it adds. Wi-Fi and Bluetooth drivers usually arrive with the regular updates.
When a device misbehaves (the printer won’t connect, the monitor has the wrong resolution), note its exact model, usually on a sticker, along with the evidence listed in “Gather evidence before asking for help” below.
9.8 Troubleshooting playbook (student-friendly)
When your computer stops doing what you expect, the natural reaction is to try fifteen things at once in a panic. That usually makes things worse: when something finally works you don’t know which change fixed it, and another change may have broken something new. The reliable way is the opposite: a short list of cheap checks, tried one at a time, until the problem goes away or becomes clearer. It’s deliberately boring, and most problems don’t get past the first few steps.
Start with the simplest reversible steps
Each of these takes about a minute. Try them in order.
Quit and reopen the app. Really quit it, not just close its window. On a Mac, Command-Q quits an app, while Command-W only closes the window and leaves the app running. On Windows, check the system tray near the clock for apps that keep running in the background, and right-click → Exit. A surprising share of “the app is broken” problems end here.
Restart the computer. “Have you tried turning it off and on again?” is a cliché because it works. A restart clears out programs that have been slowly eating memory, resets stuck background processes, reloads drivers, and finishes any pending updates. Choose Restart, not Sleep: waking from sleep resets nothing.
Check free disk space, as described earlier. If you’re down to the last few percent, that’s very likely the real problem. Free some space before trying anything else.
Check your network connection. Does a different website load? Does another app on the same network work? A lot of “the app is broken” turns out to be “the Wi-Fi dropped and the app handled it badly.”
Ask what changed. Did you install something yesterday? Did an update run overnight? Did you change a setting? Most “it was working yesterday” problems come from one specific recent change you can find.
If none of that helped, you’ve still learned something: the problem is real, and it’s worth escalating to the tools below.
Use safe mode when normal startup fails
Both systems have a safe mode that starts the computer with only the essentials, skipping third-party drivers, login items, and extensions. It’s the right tool when a normal startup fails, or when the system is too broken to troubleshoot from inside.
macOS (Apple silicon): Shut down → hold the power button until "Loading
startup options" appears → select your startup disk →
hold Shift and click "Continue in Safe Mode"
macOS (Intel): Turn on and immediately hold Shift until the login
window appears; "Safe Boot" shows in the corner.
Windows: Hold Shift while clicking Restart → Troubleshoot →
Advanced options → Startup Settings → Restart →
press 4 or F4 for Safe Mode (5 or F5 adds networking)On Windows, if your drive is encrypted, have your BitLocker recovery key handy before you start; Microsoft’s startup settings page says you’ll need it. If everything works in safe mode but not normally, the culprit is something that loads during a normal startup: a third-party driver, a login item, a background extension. Restart normally, turn the suspects off one at a time, and the one whose removal fixes the problem is your answer.
Gather evidence before asking for help
When the playbook runs out and you need a TA or a help desk, the quality of your question decides how fast you get an answer (see Chapter 2). Collect this first:
- OS version and build (from “Check OS version and build” above).
- Device model (Windows: Settings → System → About → “Device specifications”; macOS: Apple menu → About This Mac).
- Free disk space, because it’s the first thing anyone will ask about.
- The exact error message. Not “it says there’s an error,” but the exact text, copied and pasted if you can, or a screenshot if the text can’t be selected.
- When it happens. At startup? When you open one particular app? After a particular action?
- Steps to reproduce. What do you do, in order, to make it happen? Does it happen every time, or only sometimes?
- What changed recently. Updates installed, apps added or removed, settings changed, files moved.
Paste text rather than screenshots whenever you can: a helper can search, quote, and copy text, but not a picture. Save screenshots for problems that really are visual, such as a dialog whose text you can’t select.
9.9 A semester maintenance schedule
Everything above works best as a routine, spread thinly across the semester so nothing piles up. It takes about an hour a month, and its real job is to make sure you never think “when did I last back up?” at 11 p.m. the night before a deadline.
Weekly rituals (about 10 minutes)
Once a week, ideally at the same time (the end of a Sunday study session works well), run a quick health check:
Weekly checklist:
[ ] Check for pending OS updates; install security patches
[ ] Confirm the last backup ran within the past day
[ ] Glance at free disk space; clean up if under 15%
[ ] Empty the Trash / Recycle Bin
[ ] Restart the computer at least once this weekThe restart is the one people forget. Laptops sleep when you close the lid and can go weeks without a real restart, while background programs pile up; a Sunday-night restart starts the week clean.
Monthly deep check (about 20–30 minutes)
Once a month, look at the things that change too slowly to need weekly attention:
Monthly checklist:
[ ] Install any pending feature updates (if you have time to recover)
[ ] Review and prune startup / login items
[ ] Uninstall apps you haven't used in months
[ ] Glance at the Downloads folder and clear it out
[ ] Verify the backup by restoring one random file
[ ] Update your primary editor and its extensions
[ ] Update conda, pip, and any other package managers you rely onOf all of these, “restore one random file” matters most and is the easiest to skip; two minutes a month keeps your backup honest.
Before major milestones (projects, finals, deadlines)
In the week before a big deadline or exam, flip the strategy: aim for the least risk, not the newest features. The rule is don’t change anything you don’t have to.
Pre-deadline checklist:
[ ] Backups are current AND you have verified you can restore from them
[ ] Free disk space is above 15%
[ ] Do NOT install major OS upgrades or feature updates
[ ] Do NOT upgrade conda, pip, or any package in your active environment
[ ] Confirm your core tools still run end-to-end:
- editor opens the project
- conda/venv activates
- jupyter notebook launches
- the project's main script or notebook runs from a clean start
[ ] Have a second machine or cloud backup available for emergency accessThat last line deserves real thought. What’s your plan if your laptop dies at 8 p.m. the night before a submission? If the honest answer is “panic,” spend an hour now: push your code to GitHub, find the nearest lab or library computer, and make sure your work runs on a borrowed machine. The plan doesn’t have to be fancy; it just has to exist before you need it.
9.10 Stakes and politics
On October 14, 2025, Microsoft stopped providing free security updates for Windows 10. Plenty of those PCs still worked fine, but many couldn’t take the free upgrade to Windows 11, whose system requirements include a Trusted Platform Module 2.0 chip and a processor on Microsoft’s approved list. Microsoft’s advice for those machines was to enroll in an Extended Security Updates program or replace the device. A student with a hand-me-down laptop had no say in that calendar, and every laptop replaced early added to the world’s electronic waste.
That decision shows how much of this chapter is set by someone other than you. The vendor decides when your hardware stops getting patches, so the advice to “install every security update” quietly assumes you can afford a machine that still receives them. Whoever holds administrator rights decides what you can install: on your own laptop that’s you, but on a lab computer or a work-issued one it’s the institution, and that shapes which courses and tools you can actually use. And the defaults decide what flows back to the vendor. Telemetry, crash reports, and advertising settings can be adjusted on both systems, within limits, but some of them are on unless you turn them off.
See Chapter 8 for the broader framework. The concrete prompt to carry forward: when a tool won’t run, asks for permissions you can’t grant, or stops being supported on your hardware, ask who decided, and who pays for the decision.
9.11 Worked examples
Setting up a safe update routine
You want your computer patched without an update ever interrupting an exam again. On Windows, open Settings → Windows Update and click “Check for updates” to clear anything pending. Then open Advanced options → Active hours and set a window that covers your classes and usual study time; Windows won’t restart for updates inside it. On macOS, open System Settings → General → Software Update, click the (i) next to Automatic Updates, and turn on downloading new updates, installing macOS updates, and installing security responses and system files. Either way, the restart still waits for you, but you no longer have to remember to check.
Then build the habit from the weekly checklist: when an update is waiting, install it on a quiet evening rather than dismissing the reminder until the system forces a restart at 2 a.m. before a deadline.
Configuring backups and testing a restore
Start with the free layer: turn on folder backup to your school’s OneDrive (or iCloud’s Desktop & Documents Folders on a Mac) and check that your files show up on the web. Then suppose you have an external drive, bought or borrowed, with room to spare. On Windows, plug it in, search the Start menu for File History, choose the drive, and turn it on; within a few minutes the “files last copied” time should update. On a Mac, plug it in, open System Settings → General → Time Machine, click Add Backup Disk, and choose the drive; the first backup starts right away and can take a while, so leave the drive connected.
Now do the half people skip. Create a file called restore-test.txt in Documents, wait for the next backup to run, and then delete the file and empty the Trash or Recycle Bin. On Windows, right-click the Documents folder, choose Restore previous versions, open an earlier version, and restore the file. On a Mac, open Documents, open the Time Machine app, step back to before the deletion, select the file, and click Restore. If it comes back, you know the system works and how to use it under stress. If it doesn’t, you’ve found the problem (the wrong drive, a folder that isn’t included, a backup that never ran) on a calm afternoon instead of the day you need it.
Recovering from a broken update
Sometimes an update does break something: Windows installs updates and your Wi-Fi stops working, or you upgrade macOS and an app you need won’t launch.
Start by working out what changed. On Windows, Settings → Windows Update → Update history lists recent updates with their dates and KB numbers. On macOS, hold Option, click the Apple menu, choose System Information, and look under Software → Installations. Compare the dates: if the trouble started right after a particular update, that’s your suspect. Search for its KB number or name together with the symptom; if it’s a known problem, other people have already hit it, and the workaround is usually written up.
If you need to undo it, Windows lets you uninstall many recent updates from the same Update history page (Uninstall updates), and after a feature update you can go back to the previous version for 10 days, according to Microsoft’s recovery options page. macOS has no undo button for an upgrade; going back generally means reinstalling the earlier macOS and restoring your files from a Time Machine backup made before the upgrade, which is one more reason to have that backup. If the computer won’t start at all, the recovery environments described earlier can repair, restore, or reinstall. Treat reinstalling as the last option: it works, but it takes hours, and it depends on a backup you’ve already tested.
9.12 Exercises
Record your OS version, build, and device model in a troubleshooting note.
Find the update settings page and take a screenshot of where you would check for updates.
Configure a backup (Windows Backup and File History, or Time Machine) and check when the last backup ran.
Find your encryption setting (Windows device encryption or BitLocker, or macOS FileVault) and write down where the recovery key is stored (don’t paste the key itself into your notes).
Find one startup or login item you don’t need and turn it off.
Run a restore drill: bring back an older version of a document from your backup.
Find the three largest folders your coursework has created (environments, caches, datasets). For each, decide whether it could be rebuilt from a file you keep, and reclaim the space of one that can.
9.13 One-page checklist
I can find key settings (updates, backups, security, storage) using the settings search box.
I know my OS version and build and can report them.
Updates are on, and I install them on a schedule I choose.
I avoid major upgrades right before deadlines.
Backups are set up, recent, and I’ve practiced a restore.
I keep at least 15 percent of my disk free.
I know how much space my environments and caches take, and I clear caches and finished projects’ environments at the end of a term.
Screen lock is on, and my important accounts use a password manager and MFA.
Disk encryption is on, and I know where my recovery key is stored.
I can follow the troubleshooting playbook and gather evidence before asking for help.
9.14 Quick reference: where common settings live
| Task | Windows | macOS |
|---|---|---|
| Updates | Settings → Windows Update | System Settings → General → Software Update |
| Version and build | Settings → System → About | Apple menu → About This Mac |
| Storage | Settings → System → Storage | System Settings → General → Storage |
| Security | Windows Security app; Settings → Privacy & security | System Settings → Privacy & Security |
| Encryption | Settings → Privacy & security → Device encryption (or BitLocker) | Privacy & Security → FileVault |
| Backups | Control Panel → File History; Settings → Accounts → Windows Backup | System Settings → General → Time Machine |
| Startup apps | Settings → Apps → Startup | System Settings → General → Login Items & Extensions |
| Recovery | Settings → System → Recovery | macOS Recovery (see “Recovery tools” above) |
- Microsoft Support: Windows — the official help portal for Windows updates, backups, and security, and the first place to check when a menu has moved.
- Apple Support: Mac User Guide — Apple’s own guide to Software Update, Time Machine, FileVault, and every panel in System Settings; pick your macOS version at the top.
- Electronic Frontier Foundation, Surveillance Self-Defense — a calm, practical guide to threat modeling, account hardening, and platform choices; goes well beyond “use a password manager.”
- National Cybersecurity Alliance, Online Safety and Privacy Resources — plain-language guides to passwords, MFA, software updates, and account hygiene.
- iFixit Laptop Repairability Scores — laptop-by-laptop teardown ratings; a useful counterweight to vendor marketing when you’re deciding which machine to buy or repair.
- Ubuntu, Get Ubuntu — if you ever want to try a free, open-source operating system on a spare laptop, Ubuntu is the gentlest place to start.
- Microsoft, Windows release health and Apple, Apple security releases — the official lists of which versions are still getting security patches; useful when you’re deciding whether an older machine is safe to keep online.